The 2.55 (aka 255): In February 1955 Coco Chanel introduced a handbag - double flap, with mademoiselle (square) closure and mademoiselle metal chain. It became popularly known as the 2.55 flap bag. Over the years there have been many variations to the original 2.55 flapdesign: 1) the use of leather interwoven through the chain 2) use of different leathers and fabrics, 3) single flap vs. the original double flap, 4) different sizes available, etc. The term 2.55 or 255 refers to ALL FLAP STYLE BAGS including variations of the original. The original 2.55 details: The lining - The linings color represents the color of the uniforms from the convent where Coco grew up. The inside compartment there is a zippered compartment at the inside of the outer flap, that is where Coco Chanel presumably hid her love letters (from her lover at the time). The backside there is a back outside pocket on the handbag that is where Coco presumably stashed extra money. The shoulder strap as noted above Coco grew up in a convent, at the orphanage. The caretakers hold the keys at their waist dangling from the same type of chains as the 2.55 shoulder strap chains. The front lock the front lock is called the Mademoiselle Lock (because Coco was never married). Below is a picture that was posted by a PFer that presumably represents an original 2.55 flap bag. I cannot verify this information. The hardware looks two-toned and Id be surprised if an original 2.55 had two-toned hardware. In any case it is a vintage (pre-2005 reissue) 2.55 flap for sure.